Q: What is the meaning of the status 'Reviews completed'?

You have two questions, and the first is about something odd or even erroneous. You say that the status changed to ‘Reviews completed’ on September 4, and then, the date of the status changed to July 13. This is odd, and is about the time of the manuscript was ‘Under Review.’ This may be either a technical or a manual glitch. If so, and although this isn’t a very big issue, you may consider checking this with the editor.

About the second question, their turnaround time from submission to first decision (as it says on the journal site here), is 76 days. Going by the dates you have provided, it just about aligns with that time, with a delay of about a couple of weeks – which isn’t too much, given that this is a Springer journal (which tends to receive a lot of submissions).

Presently, the Associate Editor (AE) is probably going through the review comments and arriving at a decision on the manuscript. They will then convey their decision to the Editor-in-Chief (EIC), who will make the final decision (accept, reject, revise-and-resubmit, or even, reject-and-resubmit). As it’s been only about a week since the last update (except the confusion over the date), you should wait for a few days to see if the status changes. If you don’t hear from them in about a week or 10 days, you could drop them a mail asking about both the current status and the date change.

Hope that helps. For more information on the various points touched upon above, you may find the following resources useful:

• Peer review process and editorial decision making at journals
• How a journal editor reaches a decision on a manuscript after peer review
• A practical handbook of templates for communicating with the journal

All the best for the next stages of your manuscript!